/*
** $Id: lauxlib.c,v 1.248 2013/03/21 13:54:57 roberto Exp $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/


#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


/* This file uses only the official API of Lua.
** Any function declared here could be written as an application function.
*/

#define lauxlib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"


/*
** {======================================================
** Traceback
** =======================================================
*/


#define LEVELS1	12	/* size of the first part of the stack */
#define LEVELS2	10	/* size of the second part of the stack */



/*
** search for 'objidx' in table at index -1.
** return 1 + string at top if find a good name.
*/
static int findfield (lua_State *L, int objidx, int level) {
	if (level == 0 || !lua_istable(L, -1))
		return 0;  /* not found */
	lua_pushnil(L);  /* start 'next' loop */
	while (lua_next(L, -2)) {  /* for each pair in table */
		if (lua_type(L, -2) == LUA_TSTRING) {  /* ignore non-string keys */
			if (lua_rawequal(L, objidx, -1)) {  /* found object? */
				lua_pop(L, 1);  /* remove value (but keep name) */
				return 1;
			}
			else if (findfield(L, objidx, level - 1)) {  /* try recursively */
				lua_remove(L, -2);  /* remove table (but keep name) */
				lua_pushliteral(L, ".");
				lua_insert(L, -2);  /* place '.' between the two names */
				lua_concat(L, 3);
				return 1;
			}
		}
		lua_pop(L, 1);  /* remove value */
	}
	return 0;  /* not found */
}


static int pushglobalfuncname (lua_State *L, lua_Debug *ar) {
	int top = lua_gettop(L);
	lua_getinfo(L, "f", ar);  /* push function */
	lua_pushglobaltable(L);
	if (findfield(L, top + 1, 2)) {
		lua_copy(L, -1, top + 1);  /* move name to proper place */
		lua_pop(L, 2);  /* remove pushed values */
		return 1;
	}
	else {
		lua_settop(L, top);  /* remove function and global table */
		return 0;
	}
}


static void pushfuncname (lua_State *L, lua_Debug *ar) {
	if (*ar->namewhat != '\0')  /* is there a name? */
		lua_pushfstring(L, "function " LUA_QS, ar->name);
	else if (*ar->what == 'm')  /* main? */
		lua_pushliteral(L, "main chunk");
	else if (*ar->what == 'C') {
		if (pushglobalfuncname(L, ar)) {
			lua_pushfstring(L, "function " LUA_QS, lua_tostring(L, -1));
			lua_remove(L, -2);  /* remove name */
		}
		else
			lua_pushliteral(L, "?");
	}
	else
		lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
}


static int countlevels (lua_State *L) {
	lua_Debug ar;
	int li = 1, le = 1;
	/* find an upper bound */
	while (lua_getstack(L, le, &ar)) { li = le; le *= 2; }
	/* do a binary search */
	while (li < le) {
		int m = (li + le)/2;
		if (lua_getstack(L, m, &ar)) li = m + 1;
		else le = m;
	}
	return le - 1;
}


LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1,
								const char *msg, int level) {
									lua_Debug ar;
									int top = lua_gettop(L);
									int numlevels = countlevels(L1);
									int mark = (numlevels > LEVELS1 + LEVELS2) ? LEVELS1 : 0;
									if (msg) lua_pushfstring(L, "%s\n", msg);
									lua_pushliteral(L, "stack traceback:");
									while (lua_getstack(L1, level++, &ar)) {
										if (level == mark) {  /* too many levels? */
											lua_pushliteral(L, "\n\t...");  /* add a '...' */
											level = numlevels - LEVELS2;  /* and skip to last ones */
										}
										else {
											lua_getinfo(L1, "Slnt", &ar);
											lua_pushfstring(L, "\n\t%s:", ar.short_src);
											if (ar.currentline > 0)
												lua_pushfstring(L, "%d:", ar.currentline);
											lua_pushliteral(L, " in ");
											pushfuncname(L, &ar);
											if (ar.istailcall)
												lua_pushliteral(L, "\n\t(...tail calls...)");
											lua_concat(L, lua_gettop(L) - top);
										}
									}
									lua_concat(L, lua_gettop(L) - top);
}

/* }====================================================== */


/*
** {======================================================
** Error-report functions
** =======================================================
*/

LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
	lua_Debug ar;
	if (!lua_getstack(L, 0, &ar))  /* no stack frame? */
		return luaL_error(L, "bad argument #%d (%s)", narg, extramsg);
	lua_getinfo(L, "n", &ar);
	if (strcmp(ar.namewhat, "method") == 0) {
		narg--;  /* do not count `self' */
		if (narg == 0)  /* error is in the self argument itself? */
			return luaL_error(L, "calling " LUA_QS " on bad self (%s)",
			ar.name, extramsg);
	}
	if (ar.name == NULL)
		ar.name = (pushglobalfuncname(L, &ar)) ? lua_tostring(L, -1) : "?";
	return luaL_error(L, "bad argument #%d to " LUA_QS " (%s)",
		narg, ar.name, extramsg);
}


static int typeerror (lua_State *L, int narg, const char *tname) {
	const char *msg = lua_pushfstring(L, "%s expected, got %s",
		tname, luaL_typename(L, narg));
	return luaL_argerror(L, narg, msg);
}


static void tag_error (lua_State *L, int narg, int tag) {
	typeerror(L, narg, lua_typename(L, tag));
}


LUALIB_API void luaL_where (lua_State *L, int level) {
	lua_Debug ar;
	if (lua_getstack(L, level, &ar)) {  /* check function at level */
		lua_getinfo(L, "Sl", &ar);  /* get info about it */
		if (ar.currentline > 0) {  /* is there info? */
			lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline);
			return;
		}
	}
	lua_pushliteral(L, "");  /* else, no information available... */
}


LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
	va_list argp;
	va_start(argp, fmt);
	luaL_where(L, 1);
	lua_pushvfstring(L, fmt, argp);
	va_end(argp);
	lua_concat(L, 2);
	return lua_error(L);
}


LUALIB_API int luaL_fileresult (lua_State *L, int stat, const char *fname) {
	int en = errno;  /* calls to Lua API may change this value */
	if (stat) {
		lua_pushboolean(L, 1);
		return 1;
	}
	else {
		lua_pushnil(L);
		if (fname)
			lua_pushfstring(L, "%s: %s", fname, strerror(en));
		else
			lua_pushstring(L, strerror(en));
		lua_pushinteger(L, en);
		return 3;
	}
}


#if !defined(inspectstat)	/* { */

#if defined(LUA_USE_POSIX)

#include <sys/wait.h>

/*
** use appropriate macros to interpret 'pclose' return status
*/
#define inspectstat(stat,what)  \
	if (WIFEXITED(stat)) { stat = WEXITSTATUS(stat); } \
   else if (WIFSIGNALED(stat)) { stat = WTERMSIG(stat); what = "signal"; }

#else

#define inspectstat(stat,what)  /* no op */

#endif

#endif				/* } */


LUALIB_API int luaL_execresult (lua_State *L, int stat) {
	const char *what = "exit";  /* type of termination */
	if (stat == -1)  /* error? */
		return luaL_fileresult(L, 0, NULL);
	else {
		inspectstat(stat, what);  /* interpret result */
		if (*what == 'e' && stat == 0)  /* successful termination? */
			lua_pushboolean(L, 1);
		else
			lua_pushnil(L);
		lua_pushstring(L, what);
		lua_pushinteger(L, stat);
		return 3;  /* return true/nil,what,code */
	}
}

/* }====================================================== */


/*
** {======================================================
** Userdata's metatable manipulation
** =======================================================
*/

LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
	luaL_getmetatable(L, tname);  /* try to get metatable */
	if (!lua_isnil(L, -1))  /* name already in use? */
		return 0;  /* leave previous value on top, but return 0 */
	lua_pop(L, 1);
	lua_newtable(L);  /* create metatable */
	lua_pushvalue(L, -1);
	lua_setfield(L, LUA_REGISTRYINDEX, tname);  /* registry.name = metatable */
	return 1;
}


LUALIB_API void luaL_setmetatable (lua_State *L, const char *tname) {
	luaL_getmetatable(L, tname);
	lua_setmetatable(L, -2);
}


LUALIB_API void *luaL_testudata (lua_State *L, int ud, const char *tname) {
	void *p = lua_touserdata(L, ud);
	if (p != NULL) {  /* value is a userdata? */
		if (lua_getmetatable(L, ud)) {  /* does it have a metatable? */
			luaL_getmetatable(L, tname);  /* get correct metatable */
			if (!lua_rawequal(L, -1, -2))  /* not the same? */
				p = NULL;  /* value is a userdata with wrong metatable */
			lua_pop(L, 2);  /* remove both metatables */
			return p;
		}
	}
	return NULL;  /* value is not a userdata with a metatable */
}


LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
	void *p = luaL_testudata(L, ud, tname);
	if (p == NULL) typeerror(L, ud, tname);
	return p;
}

/* }====================================================== */


/*
** {======================================================
** Argument check functions
** =======================================================
*/

LUALIB_API int luaL_checkoption (lua_State *L, int narg, const char *def,
								 const char *const lst[]) {
									 const char *name = (def) ? luaL_optstring(L, narg, def) :
										 luaL_checkstring(L, narg);
									 int i;
									 for (i=0; lst[i]; i++)
										 if (strcmp(lst[i], name) == 0)
											 return i;
									 return luaL_argerror(L, narg,
										 lua_pushfstring(L, "invalid option " LUA_QS, name));
}


LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *msg) {
	/* keep some extra space to run error routines, if needed */
	const int extra = LUA_MINSTACK;
	if (!lua_checkstack(L, space + extra)) {
		if (msg)
			luaL_error(L, "stack overflow (%s)", msg);
		else
			luaL_error(L, "stack overflow");
	}
}


LUALIB_API void luaL_checktype (lua_State *L, int narg, int t) {
	if (lua_type(L, narg) != t)
		tag_error(L, narg, t);
}


LUALIB_API void luaL_checkany (lua_State *L, int narg) {
	if (lua_type(L, narg) == LUA_TNONE)
		luaL_argerror(L, narg, "value expected");
}


LUALIB_API const char *luaL_checklstring (lua_State *L, int narg, size_t *len) {
	const char *s = lua_tolstring(L, narg, len);
	if (!s) tag_error(L, narg, LUA_TSTRING);
	return s;
}


LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
										const char *def, size_t *len) {
											if (lua_isnoneornil(L, narg)) {
												if (len)
													*len = (def ? strlen(def) : 0);
												return def;
											}
											else return luaL_checklstring(L, narg, len);
}


LUALIB_API lua_Number luaL_checknumber (lua_State *L, int narg) {
	int isnum;
	lua_Number d = lua_tonumberx(L, narg, &isnum);
	if (!isnum)
		tag_error(L, narg, LUA_TNUMBER);
	return d;
}


LUALIB_API lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number def) {
	return luaL_opt(L, luaL_checknumber, narg, def);
}


LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int narg) {
	int isnum;
	lua_Integer d = lua_tointegerx(L, narg, &isnum);
	if (!isnum)
		tag_error(L, narg, LUA_TNUMBER);
	return d;
}


LUALIB_API lua_Unsigned luaL_checkunsigned (lua_State *L, int narg) {
	int isnum;
	lua_Unsigned d = lua_tounsignedx(L, narg, &isnum);
	if (!isnum)
		tag_error(L, narg, LUA_TNUMBER);
	return d;
}


LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int narg,
										lua_Integer def) {
											return luaL_opt(L, luaL_checkinteger, narg, def);
}


LUALIB_API lua_Unsigned luaL_optunsigned (lua_State *L, int narg,
										  lua_Unsigned def) {
											  return luaL_opt(L, luaL_checkunsigned, narg, def);
}

/* }====================================================== */


/*
** {======================================================
** Generic Buffer manipulation
** =======================================================
*/

/*
** check whether buffer is using a userdata on the stack as a temporary
** buffer
*/
#define buffonstack(B)	((B)->b != (B)->initb)


/*
** returns a pointer to a free area with at least 'sz' bytes
*/
LUALIB_API char *luaL_prepbuffsize (luaL_Buffer *B, size_t sz) {
	lua_State *L = B->L;
	if (B->size - B->n < sz) {  /* not enough space? */
		char *newbuff;
		size_t newsize = B->size * 2;  /* double buffer size */
		if (newsize - B->n < sz)  /* not big enough? */
			newsize = B->n + sz;
		if (newsize < B->n || newsize - B->n < sz)
			luaL_error(L, "buffer too large");
		/* create larger buffer */
		newbuff = (char *)lua_newuserdata(L, newsize * sizeof(char));
		/* move content to new buffer */
		memcpy(newbuff, B->b, B->n * sizeof(char));
		if (buffonstack(B))
			lua_remove(L, -2);  /* remove old buffer */
		B->b = newbuff;
		B->size = newsize;
	}
	return &B->b[B->n];
}


LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
	char *b = luaL_prepbuffsize(B, l);
	memcpy(b, s, l * sizeof(char));
	luaL_addsize(B, l);
}


LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) {
	luaL_addlstring(B, s, strlen(s));
}


LUALIB_API void luaL_pushresult (luaL_Buffer *B) {
	lua_State *L = B->L;
	lua_pushlstring(L, B->b, B->n);
	if (buffonstack(B))
		lua_remove(L, -2);  /* remove old buffer */
}


LUALIB_API void luaL_pushresultsize (luaL_Buffer *B, size_t sz) {
	luaL_addsize(B, sz);
	luaL_pushresult(B);
}


LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
	lua_State *L = B->L;
	size_t l;
	const char *s = lua_tolstring(L, -1, &l);
	if (buffonstack(B))
		lua_insert(L, -2);  /* put value below buffer */
	luaL_addlstring(B, s, l);
	lua_remove(L, (buffonstack(B)) ? -2 : -1);  /* remove value */
}


LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
	B->L = L;
	B->b = B->initb;
	B->n = 0;
	B->size = LUAL_BUFFERSIZE;
}


LUALIB_API char *luaL_buffinitsize (lua_State *L, luaL_Buffer *B, size_t sz) {
	luaL_buffinit(L, B);
	return luaL_prepbuffsize(B, sz);
}

/* }====================================================== */


/*
** {======================================================
** Reference system
** =======================================================
*/

/* index of free-list header */
#define freelist	0


LUALIB_API int luaL_ref (lua_State *L, int t) {
	int ref;
	if (lua_isnil(L, -1)) {
		lua_pop(L, 1);  /* remove from stack */
		return LUA_REFNIL;  /* `nil' has a unique fixed reference */
	}
	t = lua_absindex(L, t);
	lua_rawgeti(L, t, freelist);  /* get first free element */
	ref = (int)lua_tointeger(L, -1);  /* ref = t[freelist] */
	lua_pop(L, 1);  /* remove it from stack */
	if (ref != 0) {  /* any free element? */
		lua_rawgeti(L, t, ref);  /* remove it from list */
		lua_rawseti(L, t, freelist);  /* (t[freelist] = t[ref]) */
	}
	else  /* no free elements */
		ref = (int)lua_rawlen(L, t) + 1;  /* get a new reference */
	lua_rawseti(L, t, ref);
	return ref;
}


LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
	if (ref >= 0) {
		t = lua_absindex(L, t);
		lua_rawgeti(L, t, freelist);
		lua_rawseti(L, t, ref);  /* t[ref] = t[freelist] */
		lua_pushinteger(L, ref);
		lua_rawseti(L, t, freelist);  /* t[freelist] = ref */
	}
}

/* }====================================================== */


/*
** {======================================================
** Load functions
** =======================================================
*/

typedef struct LoadF {
	int n;  /* number of pre-read characters */
	FILE *f;  /* file being read */
	char buff[LUAL_BUFFERSIZE];  /* area for reading file */
} LoadF;


static const char *getF (lua_State *L, void *ud, size_t *size) {
	LoadF *lf = (LoadF *)ud;
	(void)L;  /* not used */
	if (lf->n > 0) {  /* are there pre-read characters to be read? */
		*size = lf->n;  /* return them (chars already in buffer) */
		lf->n = 0;  /* no more pre-read characters */
	}
	else {  /* read a block from file */
		/* 'fread' can return > 0 *and* set the EOF flag. If next call to
		'getF' called 'fread', it might still wait for user input.
		The next check avoids this problem. */
		if (feof(lf->f)) return NULL;
		*size = fread(lf->buff, 1, sizeof(lf->buff), lf->f);  /* read block */
	}
	return lf->buff;
}


static int errfile (lua_State *L, const char *what, int fnameindex) {
	const char *serr = strerror(errno);
	const char *filename = lua_tostring(L, fnameindex) + 1;
	lua_pushfstring(L, "cannot %s %s: %s", what, filename, serr);
	lua_remove(L, fnameindex);
	return LUA_ERRFILE;
}


static int skipBOM (LoadF *lf) {
	const char *p = "\xEF\xBB\xBF";  /* Utf8 BOM mark */
	int c;
	lf->n = 0;
	do {
		c = getc(lf->f);
		if (c == EOF || c != *(const unsigned char *)p++) return c;
		lf->buff[lf->n++] = c;  /* to be read by the parser */
	} while (*p != '\0');
	lf->n = 0;  /* prefix matched; discard it */
	return getc(lf->f);  /* return next character */
}


/*
** reads the first character of file 'f' and skips an optional BOM mark
** in its beginning plus its first line if it starts with '#'. Returns
** true if it skipped the first line.  In any case, '*cp' has the
** first "valid" character of the file (after the optional BOM and
** a first-line comment).
*/
static int skipcomment (LoadF *lf, int *cp) {
	int c = *cp = skipBOM(lf);
	if (c == '#') {  /* first line is a comment (Unix exec. file)? */
		do {  /* skip first line */
			c = getc(lf->f);
		} while (c != EOF && c != '\n') ;
		*cp = getc(lf->f);  /* skip end-of-line, if present */
		return 1;  /* there was a comment */
	}
	else return 0;  /* no comment */
}


LUALIB_API int luaL_loadfilex (lua_State *L, const char *filename,
							   const char *mode) {
								   LoadF lf;
								   int status, readstatus;
								   int c;
								   int fnameindex = lua_gettop(L) + 1;  /* index of filename on the stack */
								   if (filename == NULL) {
									   lua_pushliteral(L, "=stdin");
									   lf.f = stdin;
								   }
								   else {
									   lua_pushfstring(L, "@%s", filename);
									   lf.f = fopen(filename, "r");
									   if (lf.f == NULL) return errfile(L, "open", fnameindex);
								   }
								   if (skipcomment(&lf, &c))  /* read initial portion */
									   lf.buff[lf.n++] = '\n';  /* add line to correct line numbers */
								   if (c == LUA_SIGNATURE[0] && filename) {  /* binary file? */
									   lf.f = freopen(filename, "rb", lf.f);  /* reopen in binary mode */
									   if (lf.f == NULL) return errfile(L, "reopen", fnameindex);
									   skipcomment(&lf, &c);  /* re-read initial portion */
								   }
								   if (c != EOF)
									   lf.buff[lf.n++] = c;  /* 'c' is the first character of the stream */
								   status = lua_load(L, getF, &lf, lua_tostring(L, -1), mode);
								   readstatus = ferror(lf.f);
								   if (filename) fclose(lf.f);  /* close file (even in case of errors) */
								   if (readstatus) {
									   lua_settop(L, fnameindex);  /* ignore results from `lua_load' */
									   return errfile(L, "read", fnameindex);
								   }
								   lua_remove(L, fnameindex);
								   return status;
}


typedef struct LoadS {
	const char *s;
	size_t size;
} LoadS;


static const char *getS (lua_State *L, void *ud, size_t *size) {
	LoadS *ls = (LoadS *)ud;
	(void)L;  /* not used */
	if (ls->size == 0) return NULL;
	*size = ls->size;
	ls->size = 0;
	return ls->s;
}


LUALIB_API int luaL_loadbufferx (lua_State *L, const char *buff, size_t size,
								 const char *name, const char *mode) {
									 LoadS ls;
									 ls.s = buff;
									 ls.size = size;
									 return lua_load(L, getS, &ls, name, mode);
}


LUALIB_API int luaL_loadstring (lua_State *L, const char *s) {
	return luaL_loadbuffer(L, s, strlen(s), s);
}

/* }====================================================== */



LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
	if (!lua_getmetatable(L, obj))  /* no metatable? */
		return 0;
	lua_pushstring(L, event);
	lua_rawget(L, -2);
	if (lua_isnil(L, -1)) {
		lua_pop(L, 2);  /* remove metatable and metafield */
		return 0;
	}
	else {
		lua_remove(L, -2);  /* remove only metatable */
		return 1;
	}
}


LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
	obj = lua_absindex(L, obj);
	if (!luaL_getmetafield(L, obj, event))  /* no metafield? */
		return 0;
	lua_pushvalue(L, obj);
	lua_call(L, 1, 1);
	return 1;
}


LUALIB_API int luaL_len (lua_State *L, int idx) {
	int l;
	int isnum;
	lua_len(L, idx);
	l = (int)lua_tointegerx(L, -1, &isnum);
	if (!isnum)
		luaL_error(L, "object length is not a number");
	lua_pop(L, 1);  /* remove object */
	return l;
}


LUALIB_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) {
	if (!luaL_callmeta(L, idx, "__tostring")) {  /* no metafield? */
		switch (lua_type(L, idx)) {
		case LUA_TNUMBER:
		case LUA_TSTRING:
			lua_pushvalue(L, idx);
			break;
		case LUA_TBOOLEAN:
			lua_pushstring(L, (lua_toboolean(L, idx) ? "true" : "false"));
			break;
		case LUA_TNIL:
			lua_pushliteral(L, "nil");
			break;
		default:
			lua_pushfstring(L, "%s: %p", luaL_typename(L, idx),
				lua_topointer(L, idx));
			break;
		}
	}
	return lua_tolstring(L, -1, len);
}


/*
** {======================================================
** Compatibility with 5.1 module functions
** =======================================================
*/
#if defined(LUA_COMPAT_MODULE)

static const char *luaL_findtable (lua_State *L, int idx,
								   const char *fname, int szhint) {
									   const char *e;
									   if (idx) lua_pushvalue(L, idx);
									   do {
										   e = strchr(fname, '.');
										   if (e == NULL) e = fname + strlen(fname);
										   lua_pushlstring(L, fname, e - fname);
										   lua_rawget(L, -2);
										   if (lua_isnil(L, -1)) {  /* no such field? */
											   lua_pop(L, 1);  /* remove this nil */
											   lua_createtable(L, 0, (*e == '.' ? 1 : szhint)); /* new table for field */
											   lua_pushlstring(L, fname, e - fname);
											   lua_pushvalue(L, -2);
											   lua_settable(L, -4);  /* set new table into field */
										   }
										   else if (!lua_istable(L, -1)) {  /* field has a non-table value? */
											   lua_pop(L, 2);  /* remove table and value */
											   return fname;  /* return problematic part of the name */
										   }
										   lua_remove(L, -2);  /* remove previous table */
										   fname = e + 1;
									   } while (*e == '.');
									   return NULL;
}


/*
** Count number of elements in a luaL_Reg list.
*/
static int libsize (const luaL_Reg *l) {
	int size = 0;
	for (; l && l->name; l++) size++;
	return size;
}


/*
** Find or create a module table with a given name. The function
** first looks at the _LOADED table and, if that fails, try a
** global variable with that name. In any case, leaves on the stack
** the module table.
*/
LUALIB_API void luaL_pushmodule (lua_State *L, const char *modname,
								 int sizehint) {
									 luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 1);  /* get _LOADED table */
									 lua_getfield(L, -1, modname);  /* get _LOADED[modname] */
									 if (!lua_istable(L, -1)) {  /* not found? */
										 lua_pop(L, 1);  /* remove previous result */
										 /* try global variable (and create one if it does not exist) */
										 lua_pushglobaltable(L);
										 if (luaL_findtable(L, 0, modname, sizehint) != NULL)
											 luaL_error(L, "name conflict for module " LUA_QS, modname);
										 lua_pushvalue(L, -1);
										 lua_setfield(L, -3, modname);  /* _LOADED[modname] = new table */
									 }
									 lua_remove(L, -2);  /* remove _LOADED table */
}


LUALIB_API void luaL_openlib (lua_State *L, const char *libname,
							  const luaL_Reg *l, int nup) {
								  luaL_checkversion(L);
								  if (libname) {
									  luaL_pushmodule(L, libname, libsize(l));  /* get/create library table */
									  lua_insert(L, -(nup + 1));  /* move library table to below upvalues */
								  }
								  if (l)
									  luaL_setfuncs(L, l, nup);
								  else
									  lua_pop(L, nup);  /* remove upvalues */
}

#endif
/* }====================================================== */

/*
** set functions from list 'l' into table at top - 'nup'; each
** function gets the 'nup' elements at the top as upvalues.
** Returns with only the table at the stack.
*/
LUALIB_API void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) {
	luaL_checkversion(L);
	luaL_checkstack(L, nup, "too many upvalues");
	for (; l->name != NULL; l++) {  /* fill the table with given functions */
		int i;
		for (i = 0; i < nup; i++)  /* copy upvalues to the top */
			lua_pushvalue(L, -nup);
		lua_pushcclosure(L, l->func, nup);  /* closure with those upvalues */
		lua_setfield(L, -(nup + 2), l->name);
	}
	lua_pop(L, nup);  /* remove upvalues */
}


/*
** ensure that stack[idx][fname] has a table and push that table
** into the stack
*/
LUALIB_API int luaL_getsubtable (lua_State *L, int idx, const char *fname) {
	lua_getfield(L, idx, fname);
	if (lua_istable(L, -1)) return 1;  /* table already there */
	else {
		lua_pop(L, 1);  /* remove previous result */
		idx = lua_absindex(L, idx);
		lua_newtable(L);
		lua_pushvalue(L, -1);  /* copy to be left at top */
		lua_setfield(L, idx, fname);  /* assign new table to field */
		return 0;  /* false, because did not find table there */
	}
}


/*
** stripped-down 'require'. Calls 'openf' to open a module,
** registers the result in 'package.loaded' table and, if 'glb'
** is true, also registers the result in the global table.
** Leaves resulting module on the top.
*/
LUALIB_API void luaL_requiref (lua_State *L, const char *modname,
							   lua_CFunction openf, int glb) {
								   lua_pushcfunction(L, openf);
								   lua_pushstring(L, modname);  /* argument to open function */
								   lua_call(L, 1, 1);  /* open module */
								   luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");
								   lua_pushvalue(L, -2);  /* make copy of module (call result) */
								   lua_setfield(L, -2, modname);  /* _LOADED[modname] = module */
								   lua_pop(L, 1);  /* remove _LOADED table */
								   if (glb) {
									   lua_pushvalue(L, -1);  /* copy of 'mod' */
									   lua_setglobal(L, modname);  /* _G[modname] = module */
								   }
}


LUALIB_API const char *luaL_gsub (lua_State *L, const char *s, const char *p,
								  const char *r) {
									  const char *wild;
									  size_t l = strlen(p);
									  luaL_Buffer b;
									  luaL_buffinit(L, &b);
									  while ((wild = strstr(s, p)) != NULL) {
										  luaL_addlstring(&b, s, wild - s);  /* push prefix */
										  luaL_addstring(&b, r);  /* push replacement in place of pattern */
										  s = wild + l;  /* continue after `p' */
									  }
									  luaL_addstring(&b, s);  /* push last suffix */
									  luaL_pushresult(&b);
									  return lua_tostring(L, -1);
}


static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
	(void)ud; (void)osize;  /* not used */
	if (nsize == 0) {
		free(ptr);
		return NULL;
	}
	else
		return realloc(ptr, nsize);
}


static int panic (lua_State *L) {
	luai_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n",
		lua_tostring(L, -1));
	return 0;  /* return to Lua to abort */
}


LUALIB_API lua_State *luaL_newstate (void) {
	lua_State *L = lua_newstate(l_alloc, NULL);
	if (L) lua_atpanic(L, &panic);
	return L;
}


LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver) {
	const lua_Number *v = lua_version(L);
	if (v != lua_version(NULL))
		luaL_error(L, "multiple Lua VMs detected");
	else if (*v != ver)
		luaL_error(L, "version mismatch: app. needs %f, Lua core provides %f",
		ver, *v);
	/* check conversions number -> integer types */
	lua_pushnumber(L, -(lua_Number)0x1234);
	if (lua_tointeger(L, -1) != -0x1234 ||
		lua_tounsigned(L, -1) != (lua_Unsigned)-0x1234)
		luaL_error(L, "bad conversion number->int;"
		" must recompile Lua with proper settings");
	lua_pop(L, 1);
}

